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Six Subaru Powered Airplanes (5 RVs)

Very interesting. Nice to see some successful applications of the Subaru.

Depends on how you define success.

Remember, I like alternate engines. However, to be pragmatic, none of these RVs compare favorably with conventionally powered versions. They require far more maintenance per flight hour, yet lifetime reliability still isn't on par. High installed weight means no practical payload. And they are generally slower.

Some kids insist on blue hair and tattoos. That's their right, but it tends to compromise life in the larger world, like employment.
 
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Depends on how you define success.

Remember, I like alternate engines. However, to be pragmatic/I], none of these RVs compare favorably with conventionally powered versions. They require far more maintenance per flight hour, yet lifetime reliability still isn't on par. High installed weight means no practical payload. And they are generally slower.

Some kids insist on blue hair and tattoos. That's their right, but it tends to compromise life in the larger world, like employment.


There are trade offs to every choice/decision made on aircraft and engines. Andy has had pretty good service from his, likewise Russell. Some tinkering in the early days is usual.

Like many RVs fitted with Lycs, all these Sube RVs have raised the gross weight so useful load is still useful.

Shane's stock 7 easily outperformed any atmo 360 powered 7 that I've heard of, unless you know one that can true over 200 knots. It required almost no unusual maintenance in the time it flew.

The intention of the video was informational for those interested and to dispel the common misconception that auto engines won't last in aircraft.

I included a cross section of some folks I knew running these engines for a long time to share their experiences both good and bad. Subes aren't for everyone, nor even for the masses and I don't advocate as such. I showed what they weighed, how they performed and some of the common problems reported. It isn't all roses for sure and owners need to accept that reality.

Lycs/ clones have their warts too as we've seen many times here on VAF, multiple crank issues, separated barrels, cracked rocker pedestals, stuck valves, oil pump ADs, piston pin plugs, shredded drive gears, camshaft corrosion etc. Choose your poison... Lots of Lycs and clones don't make it to TBO without some major work and some Superior engines don't even make it to the starting line...

If my Sube goes south tomorrow, I can replace the entire engine for $3K or probably fix it for a few hundred. That's attractive to me and many others.
 
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Nice job

Thanks for doing this Ross. My airplane has been very low maintenance since the gearbox and flywheel update over 10 years ago. I expect to get another 500 or so hours out of my current engine and then spend a few hundred dollars to overhaul my spare engine for use.

-Andy
 
Thanks for doing this Ross. My airplane has been very low maintenance since the gearbox and flywheel update over 10 years ago. I expect to get another 500 or so hours out of my current engine and then spend a few hundred dollars to overhaul my spare engine for use.

-Andy

I appreciate your info Andy and many people have watched and commented so it must have been interesting. I may do a Part 2 with some more examples as a couple more Sube guys have already contacted me less than 12 hours after the upload.
 
If you are using a Subaru engine, are you including the FADEC system? No more mixture control?

How do they work at high altitude? I have a Subaru and I have driven it in Colorado at 12,000 feet and above over some of the high passes. But my RV can climb into the flight levels using a Lycoming. Does the Subaru FADEC still work well above normal automobile altitudes?
 
If you are using a Subaru engine, are you including the FADEC system? No more mixture control?

How do they work at high altitude? I have a Subaru and I have driven it in Colorado at 12,000 feet and above over some of the high passes. But my RV can climb into the flight levels using a Lycoming. Does the Subaru FADEC still work well above normal automobile altitudes?

All of these are EFI.

Not sure how high Andy and Russell have gone with the factory ECU? Maybe they can comment. I've been to 15,500 with my SDS and have customers who've gone to 20,000, no issues as the SDS ECU looks at MAP and baro and trims fuel accordingly.
 
EFI

I’ve flown as high as 14,500 in mine. I don’t know if the builder went higher than that during phase 1. I don’t expect to have any problems above that altitude. The mixture is adjusted automatically by the stock ECU. The only control I have over it is by adjusting the fuel pressure using the adjustable fuel pressure regulator. I don’t have a wide band O2 sensor so I don’t know for sure how rich or lean it runs. Based on fuel flow and spark plug condition, it looks like it stays pretty close to stoichiometric. It runs much leaner than a Lycoming during takeoff and climb based on fuel flow.

-Andy
 
Depends on how you define success.
Remember, I like alternate engines. However, to be pragmatic/I], none of these RVs compare favorably with conventionally powered versions. They require far more maintenance per flight hour, yet lifetime reliability still isn't on par. High installed weight means no practical payload. And they are generally slower.
Some kids insist on blue hair and tattoos. That's their right, but it tends to compromise life in the larger world, like employment.

To me, success is making making a 'non traditional engine' work by overcoming whatever challenges presented themselves. I expected some teething problems, and was not disappointed :rolleyes: That was the first couple of years. After that, it has been a no problem workhorse. I have people regularly tell me how smooth and powerful it sounds.

My Subie requires no more maintenance than my son's Mattituck. And everything costs much less!! When I decided to have my valves ground, the bill for both heads was $600 :cool:

Lifetime reliability remains to be seen (for my life anyway), but I fully expect my engine to last longer than I will be flying it. The way auto companies test engines (I worked for GM for 25 years) is way beyond what my airplane will ever throw at it.
Keeping it cool enough, and properly fed are the areas that need proper attention. I did cowl mods to allow proper temp management, and Ross's ECU has been outstanding for keeping the proper amount of fuel flowing at any altitude (No O2, so I've only gone up to 12,500).

Now I just get in and FLY!
 
My Sube engine didn't require much extra attention for the first 350 hours, just oil changes and a couple plug changes. The gearbox was never off the engine in that time. Kudos to Marcotte for designing a very solid gearbox.

After my rebuild due to higher than desired oil consumption (about the same as many Lycomings) The valves didn't like 100LL apparently and the rebuild cost less than $1000. I took the opportunity to mod a few things I thought I could improve (and did). That was satisfying.

The next nearly 100 hours was just oil changes. It runs the same every day.

I think Russell summed up the why, pretty well in a recent email to me: "I prefer not to follow all the other sheep and repeat what has been many, many times before". Different strokes for different folks.

I didn't want another Lycoming powered RV either. There are already 10,000 of them. A Lycoming was never in the cards for me. It doesn't turn my crank in any way. I am an engine guy and love to experiment. I had plenty of that to get where I am today...
 
I really applaud you tinkerers out there who want to experiment with auto engines. I don't have the tools, and more importantly the time at the moment to venture on the path less traveled. Perhaps until after I am in retirement, I would really like to experiment powering some type of light sport using motorcycle engines. The competitive nature of the motorcycle business pushes the boundary of light weight engines, more so than with cars.
 
The competitive nature of the motorcycle business pushes the boundary of light weight engines, more so than with cars.

One of the aircraft featured in Ross's videos is local to me. It's the 3.3L six cylinder Subie on the Cozy Mk IV. The builder/owner/pilot of this aircraft is a very methodical engineer who does not easily accept compromise. The quality of engineering and construction in his aircraft reflect that uncompromising spirit. I've flown the aircraft and have to say the sensation of that engine just pushing you forward smoothly is really quite something to feel. Totally unlike any Lycoming or Continental engine.

By way of contrast I offer up a local CH701 builder who used a Yamaha snowmobile engine and belt reduction drive. I've always subscribed to Ross's contention that it's typically the "other stuff" that causes non-aero engines to suffer failures. In this instance it was the engine itself that grenaded. The aircraft is now flying a Rotax 912.

With the above in mind, I would give a lot of thought to those motorcycle engines. Yes, they are well machined beasts that seem to take tons of punishment on racetracks and Baja courses. Heck, even the Honda Fit engine that is (or was) the basis of the Viking engines is a beautiful piece of modern production engineering. But what about the reduction drive necessary to get the screaming RPM's of high output motorcycle engines reduced to the range of reasonable prop speeds? It's that critical component which would give me great pause in pursuing the goal of using a motorcycle engine.

OK, we know there are a good number of BMW motorcycle engines which have been adapted to powering aircraft - I'd certainly like to learn more about them, their success rate in aircraft, their strengths and weaknesses. In the meantime I'll keep feeding my Lycoming and Continental 91 octane mogas and keep on flying until another interesting project comes along.
 
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